[zeromq-dev] Is Pub/Sub unreliable

[Martin Sustrik]

Emit Sorrels wrote:

>> This works erratically. Sometimes receiver receives less than 20
>> messages; sometimes it receives NONE.
>>
>> Is it the case that PUB/SUB sockets are unreliable? This is sort of a
>> surprise to me... If they are not, what could explain this behavior?
>> Thanks in advance.
>>
> 
> if a tree falls in the forest and no one is there to hear it does
> it make a sound? :P
> 
> afaik, pub doesn't queue up all the messages you send and resend
> old messages to subs that connect later on. it isn't used for
> such a use case.

Right. PUB/SUB works like a radio transmission. PUB is emitting 
continuous stream of messages. Individual SUBs connect, start receiving 
the stream from the point where they joined in and eventually leave the 
stream later on.

Martin